Honing apparatus



W. F. HANNON HONING APPARATUS 3 Sheets-Sheet 1 Filed May 18, 1964 V l ATTDRNEYS W. F. HANNON HONING APPARATUS 3 Sheets*Sheet Filed May 18, 1954 INVENTOR Mu /4/zf 7744 Awa/v w. F, HANNON HONING APPARATUS Se'p. 5,

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United States Patent O 3,339,312 HONING APPARATUS William F. Hannon, Berlin, Conn. Fafnir Bearing Co., New Britain, Conn. 06053) Filed May 18, 1964, Ser. No. 368,103 20 Claims. (Cl. 51-58) This invention relates to the honing of work surfaces, including circular surfaces, and more particularly to the honing of grooved races, for example ball races, especially the inner ball races of bearing rings.

Prior honing means for an inner ball race is disclosed in my U.S. Patent No. 3,094,820 and includes a holder provided with a single chamber slidably fitted with a honing stone. The holder is internally ducted to enable fluid pressure to be applied to the chamber space behind the stone for projecting it. The holder is mounted for oscillation about `an axis parallel to the end faces of a ring supported for honing and holds the stone in radial disposition within the ring. During a honing period, the ring is in rotation, the stone oscillates across the inner race surface of the ring and is urged by applied fluid pressure into honing cont-act with the race surface, honing the surface arcuately.

A particular o'bject of the invention is to advance the art of honing grooved ring races from the state represented `by said patent, to the end that such races may be honed to a high standard of brilliance more expeditiously and economically than before.

. With this particular object in view, the invention provides apparatus for honing the ball race of a ring rotating in honing position by successive application of first and second oscillatably mounted honing stones to the race surface during automatically sequenced rough and tine honing intervals of a single honing cycle. The first stone will be oscillated and projected into honing contact withthe race for the duration of the rough honing interval; the first stone then will be retracted, and the ring and stones shifted relatively to locate the second stone in honing position, after which the second stone will be projected into honing contact with the race, while oscillating, for the duration of a fine-honing interval of the cycle. Preferably, means are provided to oscillate the irst and second stones at relatively fast and slow speeds, respectively.

Specifically, the novel apparatus includes a stone holder having dual open-ended chambers spaced crosswise of vthe holder and fitted slidably with the rst and second honing stones. Dual internal passages in the holder respectively lead to the chamber spaces behind the stones and enable fluid pressure, preferably oil pressure, to be applied selectively to the stones. This holder may be called a double-barreled or dual-stone holder. It is mounted for oscillation about an axis parallel to the ring supported for honing. Means are provided for shifting 4the holder and the ring laterally with respect to each other to locate first one and then the other stone at a diametral line of the work circle, the lstone so located being then in proper disposition for honing the ring surface. f

The invention further provides a single-cycle timing device, preferably an electric or electronic arrangement,

for sequencing the apparatus through a single cyclel of H relatively rough and tine honing operations for each workpiece loaded into position to`be honed.

Features of the invention are applicable to the honing of work other than grooved inner races of bearing rings.

A 'broad object resides in the provision of a holder for selectively projected, one at a time, into honing contact with work.

An Aobject is to provide means for carrying a plurality of honing stones and means for applying them in a desired order to a work surface during a honing routine or cycle.

Another object is to provide means for mounting a plurality of honing stones for successively honing a work surface and means for moving the work and the stones relatively to locate one after another of the stones in honing relation to the work surface.

A further object is to provide means for effecting multi-stage honing of circular work by a plurality of honing stones spaced with respect to a diametral line through the Work circle and located one after another at the diametral line by relative movement between the work and stones in the direction of spacing of the stones.

Other objects and various further features of novelty and invention will be pointed out or will occur to those skilled in the art from a reading of the following specification in conjunction with the accompanying drawings. In said drawings, which show, for illustrative purposes only, preferred forms of the invention:

FIG. 1 is a fragmentary plan view of a preferred form of the honing apparatus including the dual-stone holder for lirst and second honing stones;

FIG. 2 is a fragmentary section on line 2 2 of FIG. l and shows the first honing stone radially centered in honing position within a ring workpiece supported by a carriage laterally shiftable to locate the two stones alternately in the radially centered position;

FIG. 3 is an enlarged detailed perspective view of the dual-stone holder;

FIG. 4 is a fragmentary, enlarged rear View of the apparatus and shows the dual-stone holder mounted in a rocker bar of the apparatus;

FIG. 5 is a partly sectioned detail top view of the novel stone holder;

FIG. 6 is a section on line 6-6 of FIG. 5;

FIG. 7 is a section on line 7 7 of FIG. 6 and shows the holder fitted with honing stones;

FIG. 8 schematically shows pertinent parts of the honing apparatus in conjunction wi-th a single-cycle timing commutator for sequencing the apparatus through a single honing cycle of operations for each workpiece loaded into honing position; and

FIG. 9 is a fragmentary, partly sectioned plan view of a modification wherein the honing stones are selectively located in radially centered honing position Within the ring workpiece by shifting the stone holder laterally, the View also indicating schematically timing-commutator elements and a clutch for controlling the lateral shift.

The invention is illustratively disclosed in connection with apparatus, shown in plan view in FIG. l, for honing the grooved inner race of a bearing ring W. This apparatus resembles the apparatus in FIG. 2 of said Patent 3,094,820 but has additions and changes required by the invention and including a double-barreled or dual-stone holder H. Y

Referring to FIGS. 2 to 7, the holder H comprises a body with a horizontal arm 10 integral at the rear with a vertically dependent plate-like arm 11 from the back of which integrally horizontally extends a cylindrical tail or stud 12. A rectangular prismatic lholder head 13 is integrally joined to the front of enlarged forward portion 10a of the arm 10, anda cap 14 is integrally fixed onto and covers the head 13 and the arm portion 10a. In the head 13 are dual, vertical, parallel chambers 15 and 16, of rectangular cross section, separated by a partition 13a. Each chamber is adapted to be slidably fitted with a houing stone and, for purposes of the invention, a roughing stone S1 is fitted into chamber 15 and a finishing stone S2 into chamber 16, as shown in FIGS. 2 and 7. The body and head of the holder H are formed with dual passages 17 and 18 leading into the upper ends of the chambers 15 and 16, respectively, and through which fluid pressure or suction may be applied to the blind ends of the stones in the chambers to project or retract each stone separately. Each of the passages 17 and 18 is similarly composed of sections a, b, c, d and e. The section a is a horizontal bore through the tail 12 and into the arm 11 where it meets vertical bore b; section c is a horizontal bore in the arm and connects the bore b with a vertical bore d through front section 10a of the arm 10, and section e comprises milled slots between -bore d and the upper end of an associated one of the chambers and 16. The bores a and b are closed at their outer ends by plugs 19 and 20. Side ports 21 and 22 in the tail 12 are adapted to be fitted with ends of ducts 23 and 24 (see FIG. 4) through which fluid pressure or suction is selectively communicated to the passages 17 and 18 and the associated chambers 15 and 16. The condition indicated in FIGS. 2 and 7 is one in which fluid pressure exists in passage 17 and connected chamber 15, whereby stone S1 is projected, while suction prevails in -passage 18 and cha-mber 16 to retract the stone S2. A dowel pin 25 is force-fitted into a hole, below the tail 12, formed in vertical arm 11.

The 4holder H is secured to the fiat front of an integral offset bridge 27 of a divided rocker shaft 2S (FIG. 1) which is journaled in standards 29 rising from machine base 30 and which is oscillatable -by means including a linkage 31. The trail 12 and the dowel pin 25 of the stone holder fit closely in holes in the bridge 27 (also see FIG. 4) and the flat back of the holder arm 11 is against the flat front of the bridge, a set screw 32 being tightened on a flattened top portion of the tail to keep the holder in place. As mounted on the bridge 27, the holder H extends forwardly and presents its honing stones S1 and S2 in vertical orientation within a ring workpiece W in honing position. It is to be noted that the axis of the rocker shaft is parallel to the disposition of the workpiece in honing position; i.e., parallel to a central plane throughthe race circle of the bea-ring ring W positioned for honing.

The ring W is loaded on a carriage, generally designated C (FIGS. 2 and 8) which in accordance with the invention is shiftable laterally to selectively position the ring with its radial center line or axis either in the vertical plane which includes the effective center line of honing stone S1 or in the vertical plane which includes the effective center line of honing stone S2. The carriage includes supporting shoes 33 (FIG. 2) for the ring W; blocks 34 fixedly carry the shoes and are suitably adjustably fixed (as by means 35) to a vertical slide 36. Slide 36 is shown slidable between spaced vertical guides 37 secured to the carriage proper or plate 38, which in turn is laterally slidable on a part of the machine base 30; in the sense of FIG. 2, the right-most position shown for carriage 38 is determined by a stop or lug 41 on carriage 38 striking the base part, and the left-most position thereof is determined by carriage 38 abutting a cam post 40, the displacement between these two positions being the distance D'.

The carriage 38 is normaly biased to right-most or first position (FIG. 2) by a coil spring 42 vconnected at one end to the carriage 38 and at the other end to anchor means 43 adjustably secured in a bracket 44 on the machine base 30. Mounted on the same bracket 44 is an air cylinder 45 the pressure in which is normally relieved so that its piston rod 46 is retracted from the carriage 38. After the rough-honing interval of the honing cycle (to be explained later), air pressure is applied to the cylinder 45 to drive its piston rod 46 forwardly for engaging and shifting the carriage 38 laterally to the extent of the distance D', as determined by the cam post 40. I find it convenient that the described small lateral displacement D' be effected as a small rotary displacement of carriage 38 about a frame-based pivot 39 (FIG. 8) which is preferably relatively remote from spring and actuator means 42-46. Thus, the distance D at its radius from pivot 39 is such that for the effective radial location of ring W on carriage 38 (with respect to pivot 39) the actuated displacement D' accomplishes the displacement D of ring W, thus transferring the vertical plane of the axis of ring W into alignment with the effective center line of the finishcut stone S2.

In the loaded position of a ring W, it has one face against rollers 51 and 52 (FIG. l) and its opposite face concentrically engaged by the butt end of a cylindrical sleeve 53 fixed on the end of a rotatable piston rod 54. As a preliminary to the loading of a ring W, suitable fluid pressure is applied in a line 55 to retract the rod and sleeve, enabling the ring to be freely deposited on the shoes 33 (FIG. 2). The newly loaded ring W may be elevated to working position by raising slide 36, .a double-acting hydraulic actuator 57 (FIG. 2) being shown for the purpose. Fluid pressure in line 55 is then relieved and pressure applied in line 56 to move the rod and sleeve forward. As the rod completes its forward movement, sleeve 53 engages the ring W and presses it against the rollers 51 and 52. At the end of the forward movement, the sleeve 53 bears firmly with frictional force against one face of the ring and presses the opposite face of the ring firmly against the rollers 51 and 52, whereby the ring is accurately located for honing. Then, suitable power means (not shown) rotates the rod 54 at a predetermined speed and through the sleeve 53 frictionally rotates the loaded ring W for honing during the ensuing honing cycle.

The honing cycle will be explained with particular reference to FIG. 8. The cycle involves the use of a singlecycle timing arrangement, preferably a suitable known electric timer, which is indicated diagrammatically in FIG. 8 as comprising electric timers TR1, TR2 and TRS. Associated with the timers are electric valve circuits R1, R2, R3, R4 and R5, of any suitable hold-in or trigger type, which are turned on by an operating pulse and turned off by an inhibiting or reset pulse. During the cycle, the rocker shaft 28 (see FIG. l) will be oscillated first at comparatively high speed (rough cut) and then at lower speed (finish cut). Any suitable change-speed means may be used for this purpose. As diagrammatically indicated in FIG. 8, illustrative change-speed means includes two electric clutches CL1 and CL2. Activation of CL1 clutches-in a gear 60 to a drive shaft 61. Gear 60 turns a gear 62 on a shaft 63 which carries crank wheel 64 for oscillating link age 31 (also seen FIG. l) to effect fast oscillation of the rocker shaft 28 and, thereby, of the dualstone holder H. Deactivation of the clutch CL1 uncouples gear 60 from the drive shaft 61 and fast oscillation stops. When clutch CL2 is activated, it engages a gear 65 with the drive shaft 61. Gear 65 rotates a gear 66 fast on shaft 63 to produce slow oscillation of the rocker shaft 28 and the stone holder H. Three-way valves V1, V2 and V3, of known type, are also diagrammatically shown in FIG. 8. The valves are indicated as spring-biased to a normal position. In the initial, normal positions of the valves V1 and V2, suction created by a suitable suction pump is valved to the two stone chambers, maintaining the two stones S1 and S2 retracted. Energization of a solenoid SL1 Ishifts valve V1 to supply uid pressure from a suitable source to the stone S1 for projecting it. Similarly, a solenoid SL2, when activated, conducts fluid pressure from the fluid-pressure source to the stone S2 to effect its projection. The value V3 is shifted by energization of a solenoid SLS to valve air pressure to the cylinder 45.

The ring workpiece W, being in position on the shoes 33 (FIG.'2), the honing cycle starts when the slide 36 moves up into honing position and operates a switch SW1 (diagrammatically shown in FIG. 8), causing potential from a suitable source to be applied as a starting pulse to timer TR1. The timer TR1 advances to position for operating R1, whereby the clutch CL1 is activated to bring about fast oscillation of the stone holder H. Initially, the carriage is in first lateral position where the roughing stone Slis radially located within ring W. Hence, the stone S1 now is in fast oscillation in a radial path which is perpendicular to the disposition of ring W because the oscillation axis of stone holder H is parallel to the ring disposition.

Timer TR1 advances to position for turning on R2, thereby energizing solenoid SL1 to' set the valve V1 for conducting fluid pressure to stone S1, projecting it into honing Contact with the inner-race surface of ring W. Since ring W is in rotation, the oscillating stone S1 proceeds to rough-hone the race surface. This continues until TR1 steps to position for applying a turn-olf pulse, via lead 69, to the R2 element, whereupon solenoid SL1 is deactivated, and valve V1 reapplies suction to stone S1, retracting it from the work surface. The rough-honing interval is determined by the TR1 positions for turning R2 on and off and may be varied by choice of these positions, particularly by selection of the turn-off position.

After retracting the stone S1, timer TR1 expires, that is, reaches its own cycle end, whereupon it simultaneously starts the timers TR2 and TRS, turns olf R1 (via line 70), and turns on R3.

As R1 is turned off, high-speed clutch CL1 is deactivated, and fast oscillation of the stone holder H stops.

With R3 turned on, solenoid SLS is activated, conditioning valve V3 for applying air pressure to the cylinder 45, so that its piston rod 46 is driven forward and shifts the carriage C laterally to its second position in which the finishing stone S2 is radially located within the ring W. As previously pointed out, the carriage (at ring W) is shifted a distance effectively equal to the center-to-center distance D between stones S1 and S2. This movement is controlled by the carriage cam post 40 and by stop lug 41, as has been explained. Meanwhile, TR2 turns on R4, activating clutch CL2 to initiate slow oscillation of the stone holder H.'

Timer TRS, started simultaneously with TR2, expires very shortly after the work carriage has been laterally shifted to its second position and the holder H has been set into slow oscillation. As TRS expires, it produces a turn-on pulse for R5, whereby solenoid SL2 is activated to condition valve V2 for applying pressure to stone S2 to project it into honing contact with the race surface of the ring workpiece.

TR2 advances to its expiration point and simultaneously turns olf R4 (via lead 72) and R3 (via lead 73). With R4 off, clutch 'CL2 is deactivated, and slow oscillation of the holder H stops. Since R3 also has been turned off, solenoid SLS is deactivated, whereby valve V3 relieves the pressure in cylinder 4S, retracting its piston rod 46 and allowing the carriage return spring 42'to reset the carriage C to its first lateral position, determined by stop lug 4I. The honing cycle-has thus been completed, lall the electrical and mechanical parts now being back in their original condition. Slide 36 may then be dropped or retracted by means 57, and the finished ring W may be removed and a next one inserted.

It should be understood that this multi-stage honing rout-ine is applicable, with appropriate tooling, to the honing of the outer races of rings as well as to the specifically discussed honing of inner races of rings. Instead of selectively .locating honing stones S1 an S2 at the radiaL'also diametral, center line of work ring W by shift of the work laterally, the same eect can be had by lateral, shift of the stones, and an example of means for so doing is diagrammatically showngin FIG. 9. Here the work W is 'supported in honing position exactly as in Patent 3,094,820. The dual-,stone holder H, however,

is fixed on an offset arm 270 of a laterally or axially shiftable rocker shaft I280, the right-hand part of which is slidably and rotatively journaled within standard 290a The left-hand partrof shaft 280 is non-circular and slidably engaged within acomplementary socket of a rocker shaft 280a which is purely rotatively journaled in standard 290b and may be oscillated (thereby oscillating shaft 280) at selectively fast or slow speed by means, including linkage 310, corresponding to the means described before for oscillating shaft 28 shown in FIG. l.

Fixed on the right end of shaft 280 is a grooved wheel 76 the groove of which is engaged by a roller 77a on the Vend of a lever 77. The lower arm of the lever 77 is engaged between a pair of similar in-phase cams 78 and 79, respectively fixed on the shafts of meshed gears 80 and 81 of the same size. The gear 80 is meshed with a gear 82 which is an element of any suitable known onerevolution device 83 adapted to be electrically tripped. The gear 82' is half the size of gears 80 and 81, and during a revolution of gear 82, it effects -a half-revolution of gears 80 and 81 and their cams 78 and 79. As shown in FIG. 9, the holder H is in a lateral position in which the roughing stone S1 (see FIG. 2) is at the diametral center line of the work W. After the rough-honing inter val of a honing cycle, the electrical timer TR1 (also see FIG. 8) expires and as it expires produces a pulse of potential which, in the FIG. 8 embodiment activates the solenoid SL3 associated with carriage-shifting valve V3, 'but in the FIG. 9 embodiment is applied to the trip means in device 83 to cause tripping of this device for a single revolution of the gear 80. During the revolution of gear 80, it turns the cams 78 and 79 through half a revolution, shifting lever 77 clockwise. The roller 77a on the lever thereby shifts the shaft 280 and the holder H to the right through the distance D (FIG. 2) for locating the stone S2 at the diametral center line of the work W. After the line-honing interval of the honing cycle, timer TR2 (also see FIG. 8) expires and at its expiration applies a pulse to the device 83 to cause it to be tripped again for a single `revolution of gear 82. As a result, the cams 78 and 79 feet of returning the shaft 280 and holder H to theleft,

back to the initial position shown in FIG. 9 and in which the stone S2 is again at the diametral center line of the work W, as indicated in FIG. 2.

In a specific applied example of the invention, honing is performed on very small bearing rings, the honing stones S1 and S2 each have. a lateral dimension in the order of 0.1", the distance D (FIG. 2) between the center lines of the stones is in the order of 0.11", the honing cycle takes a total time of the order of 2/10 of a minute, and the timer TRS provides a delay in the order of $500 a minute between the expiration of timer TR1 and the projection of stone S2 into honing contact with the work surface.

While the invention has been described in detail for the preferred forms shown, it will be understood that modifications may be made within the scope of the invention as dened in the claims which follow.

I claim: v

1. Honing apparatus comprising work-support means, a holder, a honing stone movably carried by the holder, means positioning the holder with the honing stone oriented toward a work surface of work supported by the work-support means, means to transmit fluid pressure directly to the honing stone to move s'aid stone, relative to the holder, from a retracted position into honing contact with the work surface, and means for alternately transmitting suction directly. to the honing stone to move said stone, relative to the holder, away from the work surface and back to said retracted position.

2. Honing apparatus comprising work-support means, 'a holder having an open-ended chamber, a honing stone slidably fitted in the chamber, means positioning the holder with the honing stone oriented toward a work surface of work supported by the work-support means, the holder being internally provided with ducting means leading to the chamber and directly to the stone, and means 'for alternately applying fluid pressure and suction directly to the stone via the ducting means and the chamber, the

7 fluid pressure directly moving the stone, relative to the holder, from a retracted position into honing contact with the work surface andthe suction alternately directly reversely moving the stone, relative to the holder, away from the work surface and back to said retracted position.

3. Apparatus as in claim 2, wherein said means for alternately -applying fluid pressure and suction further includes timing means for applying fiuid pressure to the honing stone during a honing interval and also includes timing means effective at the end of the honing interval for conditioning said means for alternately applying fluid pressure and suction, to thereby apply suction to the honing stone.

4. Honing means comprising a rigid holder integrally provided with a plurality of similarly oriented chambers each exteriorly open at the same end, a plurality of honing stones slidably fitted in the respective chambers for protrusion in the same direction from the open ends of the chambers, a plurality of internal passages in the holder respectively leading to the chamber spaces behind the respective stones, and means for selectively applying fluid pressure through said passages to the chamber spaces for selectively actuating the stones to operative protruded setting.

5. Honing means comprising a body having an arm integrally provided with dual parallel chambers extend ing transversely to the arm and in side-by-side disposition crosswise of the arm, each chamber exteriorly open at the same end, a pair of honing stones slidably fitted in the respective chambers for protrusion in the same direction from the open ends of the chambers in response to fluid pressure in the chamber spaces behind the stones, dual internal passages in the arm leading to the respective chamber spaces and through which fluid pressure is selectively applicable to the chamber spaces to actuate the stones individually to operative protruded setting.

6. Honing apparatus comprising supporting means for a workpiece, means provided with a plurality of chambers, a plurality of honing stones slidably fitted in the respective chambers, and means for selectively applying `fiuid pressure to one or another of the chambers for projecting one or another of the honing stones into honing contact with the workpiece.

7. Apparatus as in claim 6r, including means for sequencing the application of fiuid pressure to the respective chambers and thereby sequencing the projection of one stone after another to honing contact with the workpiece.

8. Apparatus as in claim 7, said sequencing means comprising timing means for determining the honing intervals of contact of the respective stones with the workpiece.

9. Apparatus as in claim 6, the chambers and hence the stones being spaced relative to a honing position, and means for effecting relative movement between the workpiece and stones in the direction of spacing of the stones to locate one stone after another at the honing position.

10. Apparatus as in claim 9, including means for sequencing said relative movement and correlating the application of fiuid pressure to the chambers with the location of the stones at honing position.

11. Apparatus for honing a circular surface of a workpiece during rotation of the workpiece, comprising means for supporting and rotating the workpiece for honing of its circular surface, a holder provided with a plurality of honing stones linearly spaced transversely of a diametral line through said circular surface, means for effecting relative movement between the |holder and the workpiece in the direction of spacing of the stones to locate one stone at a time at said diametral line, and means for effecting relative movement of the diametrally located stone and the workpiece along said diametral line to produce honing contact of the latter stone with the circular surface.

12. Apparatus to hone a grooved ring race of a work part, comprising means for supporting and rotating the work part for honing of its ring race, a dual-stone holder movably carrying first and second honing stones, means supporting the holder with the honing stones spaced in a central plane through the ring race, means to effect relative movement between the Work part and the stone holder in the direction of spacing of the stone to locate one stone at a time at a diametral line through the ring race, means for oscillating the stone holder about an axis parallel to said central plane, and means for projecting the diametrally located stone into honing contact with the race surface.

13. Apparatus as in claim 12, single-cycle means for timing the interval -of honing contact of the diametrally located, active stone with the ring race, and means controlled Iby the cycle means at the end of said interval for retracting the active stone and initiating said relative movement to locate the other stone at the diametral line.

14. Apparatus to hone a grooved ring race of a work part, comprising means for supporting and rotating the Work part for honing of its ring race, a dual-stone holder movably carrying first and second honing stones, a rocker shaft parallelling a central plane through the ring race and mounting the holder with the honing stones spaced in said central plane, means to effect relative movement between the work part and the holder in the direction of spacing of the stones to locate one stone 'at a time at a diametral line through the ring race, means for oscillating the shaft and, thereby, the holder and stones at one speed while the first stone is at the diametral line and at a different speed when the second stone is at the diametral line, means for projecting the first stone when at the diametral line into honing contact with the ring `race for a first honing interval, means for retracting the first stone from the ring race at the end of the first interval, means for then initiating said relative movement so 'as to locate the second stone at the diametral line, and means for then projecting the second stone when at the diametral line into honing contact with the -ring race for a second honing interval.

15. Apparatus for honing an inner work circle of a workpiece during rotation of the workpiece, comprising means for supporting and rotating the workpiece for honing of its inner circle, a dual-stone holder having a pair of chambers in parallel, side-by-side disposition within the breadth of the holder, each chamber exteriorly open at one end, first and second honing stones slidably fitted in the respective chambers for protrusion from their open ends, means mounting the holder with the stones inside the circle, in parallel relation to a radial line of the circle and spaced rightangularly to the radial line, means to effect relative movement between the workpiece and the holder rightangularly to the radial line in one direction for locating one of the stones at the radial line and in the opposite direction for locating the other stone at the radial line, and means for applying fluid pressure to the chamber spiace behind the lradially alined stone for projecting it into honing contact with the inner circle.

16. Apparatus as in claim 15, including cycling means, means controlled thereby for timing application of fluid pressure to the chamber of the first stone while at said radial line for a first honing interval, means controlled by the cycling means at the end of the first interval for retracting the first stone from honing contact with the work circle, means then controlled by the cycling means for initiating the relative movement for locating the second stone at the radial line, and means controlledlby the cycling means for then timing application of fluid pressure to the chamber of the second stone for a second honing interval.

17. Apparatus as in claim 16, means controlled by the cycling means for retracting the second stone at the end ofthe second honing interval, and means for then enabling the relative movement effecting means to re-locate the first stone at the radial line.

18. Apparatus as in claim 17, the means for retracting the first and second stones comprising means for applying suction to the chamber spaces behind the stones.

19. Apparatus as in claim 116, said inner circle being a grooved race, the apparatus further including means for 9 10 oscillating the dual-stone holder during the rst and sec- 2,312,012 2/1943` Wallace 51-349 011g0h01ingintferv2lS- l 19 th u t, l 2,315,062 3/1943 Kline 51-349 X ppara us as 1n calm e osci amg means l lbein-g capable of oscillating the holder at a rst speed Enhn; 51 35,8 during the lirst honing interval and :at a second, different 5 1 C a ey 51- 9 speed during the second honing interval, and means con- 3,094,820 6/1953 Hannon 51-355 trolled by the cycling means for initiating oscillation at 3,178,858 4/ 1965 Lockwood 51--291 X the required speed for a honing stone in preceding time relation to the projection of the stone into honing Contact LESTER M- SWINGLE Primary Examiner' with the race. lo

References Cited UNITED STATES PATENTS 2,076,601 4/ 1937 Strong 51-58 

1. HONING APPARATUS COMPRISING WORK-SUPPORT MEANS, A HOLDER, A HONING STONE MOVABLY CARRIED BY THE HOLDER, MEANS POSITIONING THE HOLDER WITH THE HONING STONE ORIENTED TOWARD A WORK SURFACE OF WORK SUPPORT BY THE WORK-SUPPORT MEANS, MEANS TO TRANSMIT FLUID PRESSURE DIRECTLY TO THE HONING STONE TO MOVE SAID STONE, RELATIVE TO THE HOLDER, FROM A RETRACTED POSITION INTO HONING CONTACT WITH THE WORK SURFACE, AND MEANS FOR ALTERNATELY TRANSMITTING SUCTION DIRECTLY TO THE HONING STONE TO MOVE 